Probably neither. Stereotypes are usually at their weakest and most innacurate when it keeps to P/J to the point where I find it almost meaningless. I've known way too many anal retentive Ps (especially introverts) and way too many disorganized and flighty Js (especially xxFJs)
I have an ISTJ family member who is almost completely unreliable with anything at all ever. Meanwhile, the ESFJ in my family has directly told me that I'm the most reliable person in my house and I tend to be the "go to" person both in my family and circle of friends when something needs to be done.